Chapter 3 - Circular Motion

Question 1

Angle (radians) = ?

Answer 1

Arc length/radius

θ = s/r

Question 2

Define one radian?

Answer 2

The angle subtended at the centre of a circle by an arc of equal length to the radius of the circle.

Question 3

Define centripetal force?

Answer 3

The net force acting on an object moving in a circle; it is always directed towards the centre of the circle.

Question 4

Centripetal force equation and centripetal acceleration equation?

Answer 4

F=(mv^2)/r

Since a=F/m

Centripetal acceleration, a?

a = (v^2)/r

Question 5

How to calculate orbital speed?

Answer 5

Centripetal force = (mv^2)/r is provided by the Earths gravitational pull =mg.

Therefore:
(mv^2)/r = mg
So:

(v^2)/r = g

Question 6

Define angular displacement?

Answer 6

The angle through which an object moves in a circle.